1. Technical Field
The present disclosure relates to a surgical forceps, and more particularly, to an electrosurgical forceps capable of sealing, cutting, and dissecting tissue.
2. Background of Related Art
Open or endoscopic electrosurgical forceps utilize both mechanical clamping action and electrical energy to effect hemostasis. The electrode of each opposing jaw member is charged to a different electric potential such that when the jaw members grasp tissue, electrical energy can be selectively transferred through the tissue. A surgeon can either cauterize, coagulate/desiccate and/or simply reduce or slow bleeding, by controlling the intensity, frequency and duration of the electrosurgical energy applied between the electrodes and through the tissue.
Certain surgical procedures require more than simply cauterizing tissue and rely on the combination of clamping pressure, electrosurgical energy and gap distance to “seal” tissue, vessels and certain vascular bundles. “Vessel sealing” is defined as the process of liquefying the collagen, elastin and ground substances in the tissue so that the tissue reforms into a fused mass with significantly-reduced demarcation between the opposing tissue structures.
Typically, once a vessel is sealed, the surgeon has to remove the sealing instrument from the operative site, substitute a new instrument, and accurately sever the vessel along the newly formed tissue seal. As can be appreciated, this additional step may be both time consuming (particularly when sealing a significant number of vessels) and may contribute to imprecise separation of the tissue along the sealing line due to the misalignment or misplacement of the severing instrument along the center of the tissue seal.
Several attempts have been made to design an instrument which incorporates a knife or blade member which effectively severs the tissue after forming a tissue seal. For example, U.S. Pat. No. 5,674,220 to Fox et al. discloses a transparent instrument which includes a longitudinally reciprocating knife which severs the tissue once sealed. The instrument includes a plurality of openings which enable direct visualization of the tissue during the treatment and severing processes. This direct visualization allows a user to visually and manually regulate the closure force and gap distance between jaw members to reduce and/or limit certain undesirable visual effects known to occur when treating vessels, thermal spread, charring, etc. As can be appreciated, the overall success of creating an effective tissue seal with this instrument is greatly reliant upon the user's expertise, vision, dexterity, and experience in judging the appropriate closure force, gap distance and length of reciprocation of the knife to uniformly, consistently and effectively seal the vessel and separate the tissue at the seal along an ideal cutting plane.
U.S. Pat. No. 5,702,390 to Austin et al. discloses an instrument which includes a triangularly-shaped electrode which is rotatable from a first position to treat tissue to a second position to cut tissue. Again, the user must rely on direct visualization and expertise to control the various effects of treating and cutting tissue.